Scientists and other staff at the Iranian uranium enrichment facility in Natanz marked “National Nuclear Day” on April 10 with speeches and a video showing lab-coated personnel singing a song written for the event commemorating colleagues who had been assassinated or otherwise lost over the years. Hours later, just before dawn on April 11, a powerful blast ripped through the facility.

According to information reaching the West, the explosion occurred next to the power source supplying the underground centrifuges of Iran’s main enrichment facility. (Iran also carries out enrichment at a plant in Qom but not in significant quantities.) The blast and ensuing fire caused extensive damage. Several hundred personnel on nighttime duty were evacuated and a search was undertaken for casualties. None were found.

The explosion coincided with the first visit to Israel by a senior official of the new US administration. US Defense Secretary Lloyd Austin was touring Israel’s strategic Nevatim air force base accompanied by Defense Minister Benny Gantz and Air Force Commander Maj. Gen. Amikam Norkin. As Austin was being shown Israel’s various anti-missile defenses — the Iron Dome, Arrow and David’s Sling — and a squadron of F-35 combat aircraft, Iran was accusing Israel of the sabotage at Natanz and threatening revenge against the “Zionist regime.” An Oscar-winning director could not have staged the events with such perfect timing.

“Secretary of defense, do you have a reaction to the explosion at Natanz?” the military affairs correspondent of Channel 13, Or Heller, called out to the American gazing appreciatively at the top-of-the-line weaponry. Gantz saved Austin from answering by telling Heller, jokingly, that he would “take off his head” for his rude interruption.